JP2014159344A - Hydrogen generator and fuel cell system including the same, and method for generating hydrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen generator which generates a predetermined amount of hydrogen gas by a simple mechanism and a simple process, and a fuel cell system using the same, and to provide a method for generating hydrogen.SOLUTION: A hydrogen generating agent 34 including aluminum as a main component is hung in a hydrogen generator 10 and is housed in a reaction vessel 30. The hydrogen generating agent 34 and a reaction solution 35 including an aqueous solution of an alkali metal hydroxide are made to react with each other in the reaction vessel 30 so as to generate hydrogen gas. At this moment, a reaction by-product including no alkali metal is deposited on the bottom of the reaction vessel 30 by controlling the concentration of the alkali metal hydroxide in the reaction solution 35 to be in a predetermined concentration, and simultaneously controlling a temperature of the reaction solution 35 at a predetermined value so as to prevent generation of the reaction by-product including the alkali metal.

Description

  The present invention relates to a hydrogen generator as a hydrogen supply source of a fuel cell system, and a hydrogen generation method using the hydrogen generator.

Power supply devices are installed in underwater robots and observation devices that collect data in the sea. One type of power supply device is a fuel cell. A fuel cell requires an oxygen supply source and a hydrogen generator as a hydrogen supply source.
The hydrogen generator generates hydrogen gas by bringing a hydrogen generator and a hydrogen generator into contact with each other in a reaction vessel. Hydrogen generators include metal hydrides such as NaBH ₄ , LiBH ₄ , LiH, NaH, MgH ₂ , and AlH _3, and metals such as Na, Li, Mg, K, and Al. Composed. The hydrogen generation accelerator is water or alcohol.

Patent Document 1 and Patent Document 2 disclose an apparatus for generating hydrogen by reacting metal aluminum and an alkali metal hydroxide (for example, NaOH).
Patent Document 3 discloses a hydrogen fuel generator that supplies hydrogen to a fuel cell using hydrogen as a fuel.

JP 2007-320792 A JP-T-2004-504243 Japanese Patent No. 4719838

The following requirements are required for a hydrogen generator for a fuel cell.
(1) The volume is small and the amount of hydrogen gas generated per unit volume is large. (The hydrogen gas generation mechanism must be simple.)
(2) Easy startup even at room temperature.
(3) The reaction temperature is easily controlled.
(4) The output width (hydrogen gas generation rate) can be widened, the controllability is excellent, and the stop and restart during operation can be repeated.
(5) The fuel and oxidant are not special and the operation cost is low.

In the apparatus described in Patent Document 1, it is necessary to input a metal alkali-containing material and to remove a reaction product from a reaction vessel. In the hydrogen gas atmosphere, a mechanism for controlling the input amount (symbol 8) and a solid matter discharging means ( Reference numeral 19) is provided. In addition to the cause of hydrogen leakage, these mechanisms have the problem that depending on the reaction conditions, a phenomenon such as solid matter sticking may accompany, which may cause problems such as difficulty in discharging.
In the apparatus described in Patent Document 2 and Patent Document 3, hydrogen is generated by reacting a small piece of aluminum with an aqueous solution of sodium hydroxide (NaOH). This method requires an aluminum charging mechanism. Further, since NaOH is consumed by the reaction, it is necessary to supply a large amount of NaOH aqueous solution in order to continue the reaction, and a reaction container having a large volume and an NaOH supply source are required. For this reason, there is a problem that the apparatus is complicated and large.

  The present invention provides a hydrogen generator that generates a predetermined amount of hydrogen gas by contacting a hydrogen generator and a hydrogen generator with a simple mechanism and process, a fuel cell system using the same, and a hydrogen generation method. The purpose is to do.

  In the first aspect of the present invention, a hydrogen generator containing aluminum as a main component is accommodated, a reaction capable of reacting with the hydrogen generator at the bottom, and a reaction solution containing an alkali metal hydroxide can be accommodated. Hydrogen for discharging from the reaction vessel hydrogen gas generated by the reaction of the vessel, the support that can suspend and support the hydrogen generator from the upper part of the reaction vessel, and the hydrogen generator and the reaction solution A reaction solution supply unit configured to supply water consumed in the reaction into the reaction vessel from an upper portion of the reaction vessel; and a concentration of the alkali metal hydroxide in the reaction solution within a predetermined concentration. And a control unit for controlling the temperature of the reaction solution to a predetermined value, a predetermined region at the lower end of the hydrogen generating agent is brought into contact with the reaction solution, and the hydrogen generating agent, the reaction solution, To react Together to generate the hydrogen gas amount is the reaction by-products which do not contain the alkali metal hydrogen generator which deposited on the bottom of the reaction vessel.

  According to a second aspect of the present invention, there is provided a storing step of suspending a hydrogen generator mainly composed of aluminum from an upper portion of a reaction vessel and storing the hydrogen generating agent in the reaction vessel), and a reaction solution containing an alkali metal hydroxide. The reaction solution supplying step of supplying water into the reaction vessel until the predetermined liquid level is reached in the reaction vessel, the lower end portion of the hydrogen generating agent and the reaction solution are in contact with each other, and the reaction solution The concentration of the alkali metal hydroxide is controlled within a predetermined concentration, the temperature of the reaction solution is controlled to a predetermined value, and a predetermined amount of hydrogen is reacted by the reaction between the hydrogen generating agent and the reaction solution. A hydrogen generation method including a reaction step in which a reaction by-product containing no alkali metal is deposited on the bottom of the reaction solution and a discharge step in which the hydrogen gas is discharged from the reaction vessel while generating gas. .

In the present invention, a hydrogen generating agent (aluminum) is suspended and stored in the reaction vessel, and water is supplied from the outside. There is no special mechanism for charging the hydrogen generating agent into the reaction solution. The hydrogen generator of the present invention can contact the reaction solution and the hydrogen generating agent with a simple configuration as compared with the above-mentioned patent document.
Further, the reaction is carried out under the conditions that the reaction by-product containing no alkali metal is generated by controlling the concentration of the alkali metal hydroxide in the reaction solution that reacts with the hydrogen generator and the temperature of the reaction solution. By doing so, the control of the hydrogen generation amount becomes easy. Furthermore, in the hydrogen generation reaction, only aluminum and water are consumed, and the alkali metal hydroxide acts as a catalyst and is not consumed in the reaction. Therefore, it is not necessary to supply alkali metal hydroxide from the outside for the amount consumed in the reaction. The present invention is advantageous in that the apparatus volume can be reduced and the operation cost and apparatus maintenance cost can be greatly reduced.

  1st aspect WHEREIN: The said control part is based on the pressure and temperature of the said hydrogen gas discharged | emitted from the said hydrogen discharge part, The hydroxide of the said alkali metal in the said reaction solution accommodated in the said reaction container It is preferable to control the concentration of the reaction solution to 1 mol / L or more and 14 mol / L or less, and to control the temperature of the reaction solution to 50 ° C. or more and 150 ° C. or less.

  In the second aspect, in the reaction step, a concentration of the alkali metal hydroxide in the reaction solution stored in the reaction vessel is controlled to 1 mol / L or more and 14 mol / L or less, and It is preferable that the temperature of the reaction solution is controlled to 50 ° C. or higher and 150 ° C. or lower.

  By controlling to the said density | concentration and temperature, the production | generation of the reaction by-product containing an alkali metal can be reliably prevented, ensuring a high reaction rate.

  1st aspect WHEREIN: It is preferable that the ratio of the cross-sectional area of the said hydrogen generating agent with respect to the cross-sectional area of the said reaction container is 5 to 15 times.

  2nd aspect WHEREIN: It is preferable that the ratio of the cross-sectional area of the said hydrogen generating agent with respect to the cross-sectional area of the said reaction container is 5 times or more and 15 times or less in the said reaction container.

  If it is said ratio, a hydrogen generating agent will melt | dissolve by the part which the reaction solution increased by the water supply from the reaction solution supply part. As a result, it is possible to prevent the formation of a reaction byproduct containing an alkali metal.

  In the first aspect, a first partition wall whose upper end is connected to the bottom wall of the reaction vessel and is spaced apart from the upper wall divides the internal space of the reaction vessel into a plurality of first reaction chambers, Each of the first reaction chambers contains the hydrogen generating agent, the reaction solution supply unit is provided in an upper part of one chamber of the first reaction chamber, and the reaction solution supply unit is provided in one chamber of the first reaction chamber. The other one of the first reaction chambers to which the water is supplied and the reaction solution in one chamber of the first reaction chamber is adjacent via a space between the first partition and the upper wall of the reaction vessel. It may be possible to flow into the chamber.

  In the second aspect, in the storing step, in each of the first reaction chambers, the inner space of the reaction vessel is divided into a plurality of spaces by a first partition wall whose upper end is set apart from the upper wall of the reaction vessel. In the reaction solution supplying step, the water is supplied to one chamber of the first reaction chamber, and in the reaction step, the alkali metal water is stored in one chamber of the first reaction chamber. The reaction solution containing oxide and the hydrogen generating agent in one chamber of the first reaction chamber contacted to generate the hydrogen gas, and one chamber of the first reaction chamber was filled with the reaction solution. Thereafter, the reaction solution may flow into another chamber of the first reaction chamber adjacent to the chamber of the first reaction chamber containing the reaction solution.

  When a plurality of hydrogen generating agents are accommodated in the reaction vessel, the amount of hydrogen generated in one hydrogen generator increases. At this time, if the inside of the reaction vessel is divided into a plurality of reaction chambers and hydrogen is sequentially generated in each reaction chamber, the amount of hydrogen generated can be easily controlled, and hydrogen generation can be performed for a long time.

  In the first aspect, the second partition connected to the bottom wall and the top wall of the reaction vessel divides the internal space of the reaction vessel into a plurality of second reaction chambers, and each of the second reaction chambers A partition containing the hydrogen generating agent and containing aluminum as a main component is installed at an upper part of the second partition wall, the reaction solution supply unit is provided at an upper part of one chamber of the second reaction chamber, and the reaction solution supply The part supplies the water to a chamber of the second reaction chamber, the reaction solution dissolves the partition, and the reaction solution in the chamber of the second reaction chamber is disposed through a space in which the partition is installed. May be able to flow into another chamber of the second reaction chamber adjacent thereto.

  In this case, the other chamber in the second reaction chamber contains the water, the other second reaction chamber and the reaction solution supply unit are connected via a pipe, and a pump installed in the pipe is provided. Preferably, the water in the other second reaction chamber is transported to one chamber of the second reaction chamber.

  In the second aspect, in the storing step, the reaction is performed by a second partition wall connected to a bottom wall and an upper wall of the reaction vessel, and a partition mainly composed of aluminum is installed on the upper wall side. The hydrogen generating agent is accommodated in each of the second reaction chambers in which the internal space of the container is partitioned into a plurality, and in the reaction solution supply step, the water is supplied to one chamber of the second reaction chamber, In the reaction step, the hydrogen gas is generated by contacting the reaction solution containing the alkali metal hydroxide with the hydrogen generating agent in the second reaction chamber in one chamber of the second reaction chamber. The partition and the reaction solution in the second reaction chamber come into contact with each other to react, the partition dissolves in the reaction solution, and the second reaction chamber that accommodates the reaction solution is adjacent to the first reaction chamber. 2 In the other chamber of the reaction chamber, the partition The reaction solution may be introduced through installed which was space.

  In this case, in the storing step, the water is stored in another chamber of the second reaction chamber other than the one of the second reaction chamber, and the water stored in the storing step is stored in the reaction step. The second reaction chamber is preferably transported to one chamber.

As described above, when a plurality of hydrogen generating agents are accommodated in the reaction vessel, the amount of hydrogen generation in one hydrogen generator increases. If hydrogen is sequentially generated in a plurality of reaction chambers, the amount of hydrogen generated can be easily controlled, and hydrogen generation for a long time becomes possible.
In the said aspect, water is accommodated in reaction chambers other than the reaction chamber in which reaction is performed at the time of starting, and this water is supplied to the reaction container from the reaction solution supply part. With this configuration, the amount of water supply from the outside can be reduced. Therefore, the volume of the water supply source installed outside the hydrogen generator is small, and the volume of the apparatus can be greatly reduced.

  In the first aspect, the control unit may stop the supply of water to stop the generation of the hydrogen gas, and restart the supply of water to restart the generation of the hydrogen gas. Alternatively, the apparatus further includes a support unit movable device that is capable of moving the support unit up and down at an upper portion of the reaction vessel, and the control unit drives the support unit movable device to raise the hydrogen generating agent to raise the hydrogen generator. The generation of gas may be stopped and the generation of hydrogen gas may be resumed by lowering the hydrogen generating agent.

  In the second aspect, the reaction step stops the supply of water, or stops the generation of the hydrogen gas by raising the hydrogen generating agent, and restarts the supply of water. Or a restarting step of restarting the generation of the hydrogen gas by lowering the hydrogen generating agent.

  In the hydrogen generator and the hydrogen generation method of this aspect, the generation of hydrogen during the reaction can be stopped and restarted by a simple method as described above. In particular, when the support unit movable device is provided to raise and lower the hydrogen generating agent, the hydrogen generating agent and the reaction solution can be quickly separated and contacted.

  A third aspect of the present invention is a fuel cell system provided with the hydrogen generator of the first aspect. The fuel cell is advantageous because it has a small device volume and is inexpensive to operate and maintain.

In the hydrogen generator and the hydrogen generation method of the present invention, a reaction by-product containing an alkali metal is not generated, and apparently hydrogen gas is generated by a reaction between aluminum (fuel) and water (oxidant). Since the alkali metal hydroxide is not consumed by the reaction, the amount of the alkali metal hydroxide used is small, and the amount of hydrogen gas generated per unit volume can be increased at a low operating cost.
Since the hydrogen generating apparatus and the hydrogen generating method of the present invention are reacted from the lower end of the hydrogen generating agent, contact between the hydrogen generating agent and the reaction solution can be ensured without a complicated mechanism, and the reaction is in progress. It is possible to easily stop and restart the generation of hydrogen gas.

It is a graph which shows the solid substance density | concentration which precipitates when reaction temperature and Na / Al ratio are changed in NaOH concentration of 28 mol / L. It is a graph which shows the solid substance density | concentration which precipitates when reaction temperature and Na / Al ratio are changed in NaOH concentration of 14 mol / L. When the reaction temperature and the Na / Al ratio were changed at an NaOH concentration of 7 mol / L 1 is a schematic diagram of one embodiment of a fuel cell system. It is the schematic explaining the hydrogen generator of 1st Embodiment, and the hydrogen generation method using the same. It is the schematic of an example of the cross-sectional shape of a hydrogen generating agent. It is the schematic explaining the hydrogen generator of 2nd Embodiment, and the hydrogen generating method using the same. It is the schematic explaining the hydrogen generator of 3rd Embodiment, and the hydrogen generating method using the same. It is the schematic explaining the hydrogen generator of 4th Embodiment, and the hydrogen generating method using the same. It is the schematic of a temperature control humidity tank.

The hydrogen generator and the hydrogen generation method of the present invention generate hydrogen gas using aluminum as a fuel and water as an oxidant. An alkali metal hydroxide is used as an auxiliary for this reaction. The reaction formula is as follows.
Al + MOH + 3H ₂ O → MAl (OH) ₄ + 1.5H ₂ (1)
(M: Li, Na, K)

MAl (OH) ₄ produced by the formula (1) is soluble in water, but the temperature of the reaction solution stored in the reaction vessel, the concentration of the reaction solution, the molar ratio of alkali metal to Al in the hydrogen generator. depending on the (alkali metal / Al _{ratio), Al (OH) 3,} AlO (OH), M 2 O · Al 2 O 3 · 2.5H 2 O is precipitated as a reaction by-product.

If the resulting MAl _{(OH) 4} reaction by-products including the alkali metal from _{(M 2 O · Al 2 O} 3 · 2.5H 2 O) conditions that do not precipitate the formula (1), formula (2) Thus, an alkali metal hydroxide is generated from MAl (OH) ₄ .
MAl (OH) ₄ (+ nH ₂ O) → MOH + Al (OH) ₃ (+ nH ₂ O) (2)
(M: Li, Na, K)

Therefore, unless a reaction by-product containing an alkali metal is generated, as shown in formula (3), hydrogen gas can be generated apparently from only aluminum and water, and an alkali metal hydroxide generates hydrogen. Not consumed in the reaction.
Al + 3H ₂ O → Al (OH) ₃ + 1.5H ₂ (3)

  Below, the case where the alkali metal is Na will be described as an example, and the deposition conditions for the reaction by-product will be described. FIG. 1 to FIG. 3 are simulation results of the concentration of solid matter that precipitates when the reaction temperature and the Na / Al ratio are changed in each concentration of the NaOH aqueous solution. The simulation was performed using an aqueous solution equilibrium calculation software manufactured by OLI System. 1 shows a NaOH concentration: 28 mol / L, FIG. 2 shows a NaOH concentration: 14 mol / L, and FIG. 3 shows a NaOH concentration of 7 mol / L. 1 to 3, the horizontal axis represents the Na / Al ratio, and the vertical axis represents the concentration of precipitated solid (% by mass).

The NaOH concentration of 28 mol / L (FIG. 1) is substantially the same as the concentration of the saturated aqueous NaOH solution at 20 ° C. At this concentration, Na / Al ratio of 25 ° C. in the range of 1 to 10, 50 ° C., in any of the _{80 ℃, Na 2 O · Al} 2 O 3 · 2.5H 2 O is precipitated. The amount of precipitated solids is also a high ratio of about 10% to about 40%.

The NaOH concentration of 14 mol / L (FIG. 2) is substantially the same as the concentration of 1/2 of the concentration of the saturated NaOH aqueous solution at 20 ° C. For this _{concentration,} the amount of precipitated _{Na 2 O · Al 2 O 3} · 2.5H 2 O tends to decrease. As shown in FIG. 2, 25 ° C. in _{Na 2 O · Al 2 O 3} · 2.5H 2 O precipitates. However, if the 50 ° C. or higher and Na / Al ratio of 3 or _more, it is possible to suppress the _{Na 2 O · Al 2 O 3} · 2.5H 2 O precipitation.

The NaOH concentration of 7 mol / L (FIG. 3) is substantially the same as the concentration of ¼ of the saturated NaOH aqueous solution at 20 ° C. For this _{concentration, Na 2 O · Al 2 O} 3 · 2.5H 2 O is not deposited.

From FIG. 1 to FIG. 3, the concentration of the alkali metal hydroxide in the reaction solution is 14 mol / l or less, or a concentration of 1/2 or less of the concentration of the alkali metal hydroxide in the saturated aqueous solution, and the reaction temperature is If it is 50 degreeC or more, hydrogen gas can be generated by Formula (3), without producing | generating the reaction byproduct containing an alkali metal.
Considering the reaction rate, the alkali metal hydroxide concentration needs to be 1 mol / l or more (about 1/30 of the saturated solution).
If the reaction temperature is too high, it becomes difficult to control the temperature of the reaction solution during the reaction. For this reason, it is preferable to make a reaction solution react at 150 degrees C or less.

Embodiments of the hydrogen generator of the present invention will be described below with reference to the drawings.
The hydrogen generator is applied to a fuel cell system mounted on, for example, an underwater robot or an underwater observation device. FIG. 4 is a schematic diagram of one embodiment of a fuel cell system. The fuel cell system 1 includes a fuel cell 2, an oxygen generator 5, and a hydrogen generator 10. The fuel cell 2 is connected to a lithium secondary battery 3, and the lithium secondary battery 3 is connected to a load 4.

  The fuel cell 2 is connected to the oxygen generator 5 through the oxygen supply unit 6. The oxygen generator 5 includes a container for storing liquid oxygen therein. The container for storing liquid oxygen may be a cylinder filled with high-pressure oxygen.

  The hydrogen generator 10 contains a hydrogen generating agent as fuel. The hydrogen generator 10 is connected to the fuel cell 2 through a hydrogen supply unit 7 from a hydrogen discharge unit 32 provided in the upper part. A pressure regulating valve 8 is provided in the hydrogen supply unit 7, and the flow rate at which the hydrogen gas generated by the hydrogen generator by the pressure regulating valve 8 is supplied to the fuel cell 2 can be adjusted. The hydrogen generator 10 includes a first cooler 15 that cools the reaction solution.

  A heat exchanger 9 is installed in the oxygen supply unit 6 and the hydrogen supply unit 7 immediately before oxygen and hydrogen flow into the fuel cell 2. A heat exchanger transfers the heat of hot hydrogen gas to cold oxygen. Moreover, you may install the apparatus which heats oxygen and cools hydrogen gas by another means, without installing a heat exchanger.

  The tank 11 is connected to the fuel cell 2 via a pipe. The pipe is provided with a third cooler 17 for cooling water from the fuel cell. Water discharged from the fuel cell 2 is stored in the tank 11 as an oxidant.

  The hydrogen generator 10 and the tank 11 are connected by a reaction solution supply pipe 12. The reaction solution supply pipe 12 includes a pump 13 and a second cooler 16. The reaction solution supply pipe 12 may include an activation device 14 on the downstream side (hydrogen generation device 10 side) of the pump 13. In the starter 14, an alkali metal hydroxide (solid or aqueous solution) for starting the reaction between the fuel in the hydrogen generator 10 and the oxidant is accommodated. The alkali metal hydroxide is specifically NaOH, LiOH or KOH. In the fuel cell system 1, the activation device 14 may not be installed.

  The hydrogen generator 10 includes a control unit 20. The control unit 20 is connected to a thermometer 21 and a pressure gauge 22 installed in the hydrogen supply unit 7. The thermometer 21 and the pressure gauge 22 are installed on the hydrogen gas upstream side of the pressure regulating valve 8. The control unit 20 is connected to the pump 18 of the first cooler 15, the pump 19 of the second cooler 16, and the pump 13.

<First Embodiment>
FIG. 5 is a schematic view of the hydrogen generator according to the first embodiment. The hydrogen generator 10 includes a reaction vessel 30, a support unit 31, a hydrogen discharge unit 32, and a reaction solution supply unit 33.

  The reaction vessel 30 contains a hydrogen generating agent 34 therein. The reaction vessel 30 is a pressure vessel, and a material having a corrosion resistance against the alkaline aqueous solution is selected. In FIG. 5, the first cooler is omitted.

  In this embodiment, the hydrogen generating agent 34 is mainly composed of aluminum. The purity of aluminum that can be used in this embodiment is preferably 99% or more, more preferably 99.9% or more. A support portion 31 is installed on the upper wall of the reaction vessel 30, and the support portion 31 suspends and supports the hydrogen generating agent 34 in the vertical direction. In FIG. 5, one support portion 31 and one hydrogen generating agent 34 are installed in one reaction vessel 30, but a plurality of hydrogen generating agents 34 may be supported by the plurality of supporting portions 31.

In FIG. 5, the support portion 31 is a jig that protrudes from the upper wall of the reaction vessel 30. Alternatively, a screw may be used as the support portion 31 and the hydrogen generating agent 34 may be directly fixed to the upper wall of the reaction vessel 30. Alternatively, a configuration may be adopted in which a step is provided on the upper wall of the reaction vessel 30 as the support portion 31 and the hydrogen generating agent 34 is hooked on this step.
By making the reaction vessel 30 have an inclined side wall so that the area of the bottom surface is smaller than that of the top surface, it is possible to prevent the reaction vessel 30 from slipping to the bottom even when the hydrogen generating agent 34 is dropped from the support portion 31, for example. .

  As the hydrogen generating agent 34, a columnar aluminum rod such as a cylinder or a prism can be used. The columnar hydrogen generator is easy to manufacture. Moreover, the contact area with the reaction solution can be reduced, and the controllability of the reaction system is excellent. On the other hand, in the case of a columnar shape, reaction by-products are likely to be deposited in a limited region below the hydrogen generator 34.

  Or as shown in FIG. 6, you may use the thing which combined the aluminum plate so that a hydrogen generating agent 40 may become a grid | lattice cross section. Since the hydrogen generating agent 40 of FIG. 6 has a large contact area with the reaction solution, the reaction rate (hydrogen gas generation amount per unit time) can be increased. Further, the deposition region of the reaction by-product can be made uniform.

  The hydrogen generating agent 34 has a cross-sectional area of 5 to 15 times the cross-sectional area of the reaction vessel 30. This corresponds to a multiple of the volume expansion in the case where the hydrogen generator 34 reacts to generate a reaction product that does not contain an alkali metal. By setting it in this range, when the hydrogen generator 34 and the reaction solution in the reaction vessel 30 come into contact and react as described later, the hydrogen generator (aluminum) 34 is dissolved by an increment of the reaction solution surface. Can do.

  The hydrogen discharge unit 32 and the reaction solution supply unit 33 are installed above the upper end of the hydrogen generating agent 34 supported by the support unit 31 in the reaction vessel 30. The hydrogen discharge unit 32 is connected to the hydrogen supply unit 7. The reaction solution supply unit 33 is connected to the reaction solution supply pipe 12.

  In order to ensure a high hydrogen generation amount, the fuel cell system 1 can include a plurality of the hydrogen generators 10 of FIG.

A hydrogen generation method using the hydrogen generator 10 of the first embodiment will be described with reference to FIG.
<Storage process>
The hydrogen generating agent 34 is accommodated by being suspended in the vertical direction by the support portion 31 installed on the upper wall in the reaction vessel 30. When the activation device 14 is not installed, a solid or aqueous solution of an alkali metal hydroxide (NaOH, LiOH or KOH) is accommodated in the reaction vessel 30. At this time, the alkali metal hydroxide and the hydrogen generator 34 are not brought into contact with each other.

<Reaction solution supply step (FIG. 5A)>
The pump 13 is activated and the water in the tank 11 is conveyed toward the reaction vessel 30. When installing the starting device 14 as shown in FIG. 4, water is mixed with the alkali metal hydroxide in the starting device 14. Then, an aqueous solution of an alkali metal hydroxide is supplied as a reaction solution from the starter 14 through the reaction solution supply unit 33 into the reaction vessel 30. After the starter 14 is replaced with water, water is supplied as a reaction solution into the reaction vessel 30.

  When the activation device is not provided, the water in the tank 11 is supplied from the reaction solution supply unit 33 into the reaction vessel 30 by a pump. In the reaction vessel 30, water and alkali metal hydroxide are mixed to form a reaction solution.

<Reaction process (FIG. 5A)>
The reaction solution 35 accumulated in the reaction vessel 30 and the hydrogen generating agent 34 come into contact with each other and react to generate hydrogen gas. Thereby, the hydrogen generator 10 is started.

  As the reaction continues, the hydrogen generating agent 34 is consumed, the lower end of the hydrogen generating agent 34 rises, and the liquid level of the reaction solution 35 rises. The supply of water may be continuous or intermittent.

In the present embodiment, in the reaction step, the reaction solution 35 and the hydrogen generator 34 are reacted under the condition that the reaction by-product containing the alkali metal does not precipitate. That is, the concentration of the alkali metal hydroxide in the reaction solution 35 is controlled to 1 mol / L or more and 14 mol / L or less (or a concentration of 1/2 or less of the concentration of the alkali metal hydroxide in the saturated aqueous solution). The temperature of the reaction solution is controlled to 50 ° C. or higher and 150 ° C. or lower.
Al (OH) ₃ and AlO (OH) among the reaction by-products generated by the formulas (1) to (3) under the above conditions are deposited on the bottom of the reaction vessel 30 to form a deposited layer 37.

  When the amount of reaction byproducts deposited in the reaction solution 35 increases, the reaction on the surface of the hydrogen generating agent 34 is hindered and the reaction rate decreases. In order to prevent this, the water supplied from the reaction solution supply unit 33 is supplied so that the reaction solution stored at the bottom of the reaction vessel 30 is not stirred and only the aqueous alkali metal hydroxide solution is easily generated on the surface layer. It is preferred that For example, water is supplied through the wall surface of the reaction vessel 30 or the hydrogen generating agent 34, or water is supplied by spraying.

In the situation where the reaction solution is not actively stirred as described above, the reaction by-product and the alkali metal hydroxide aqueous solution (reaction solution) have a higher specific gravity than water, and thus the reaction by-product in order from the bottom of the reaction vessel 30. Thus, a deposition layer 37, a mixed layer 36 of reaction solution and reaction by-product 36, and a layer of reaction solution 35 are formed. When the alkali metal hydroxide moves from the mixed layer 36 to the upper layer by gentle stirring or diffusion with water flowing from the reaction solution supply unit 33, the concentration of the reaction solution in the portion where the hydrogen generating agent 34 is immersed is the mixed layer. The concentration is relatively low compared to A reaction solution (alkali metal hydroxide aqueous solution) exists in the gap (between particles) between the deposited reaction by-products. This reaction solution cannot contribute to the reaction with the hydrogen generator 34. Since water is supplied from the upper part of the reaction vessel 30, the concentration of the reaction solution in the vicinity of the hydrogen generating agent 34 decreases. Therefore, during the reaction process, an aqueous solution of alkali metal hydroxide that is taken in between the reaction by-products and whose concentration is reduced is replenished from the reaction solution supply unit 33. For this purpose, the reaction vessel 30 may be provided with a concentration measuring unit for measuring the concentration of alkali metal hydroxide.
The added aqueous solution of alkali metal hydroxide is supplied from a supply path (not shown) provided in the reaction solution supply pipe 12 of FIG. The supply path may be installed on the upstream side of the pump 13 or connected to the activation device 14.

<Discharge process (FIG. 5A)>
Hydrogen generated in the reaction vessel 30 is discharged from the hydrogen discharge unit 32.
When all the hydrogen generating agents 34 in the reaction vessel 30 have reacted, the reaction step and the discharge step are finished.

The output of the fuel cell 2 is proportional to the amount of hydrogen gas generated. The amount of hydrogen gas generated in the reaction process is controlled by the following method.
The pressure and temperature of the hydrogen gas discharged from the hydrogen generator 10 are measured by the pressure gauge 22 and the thermometer 21, respectively. The control unit 20 monitors measured values of pressure and temperature.

(A) Pressure control The water supply amount Gw (kg / min) from the reaction solution supply unit 33 is expressed by the following equation.
Gw = Gwr + Gws (4)
Gwr: amount of water that reacts with the hydrogen generator (aluminum) (kg / min)
Gws: amount of water not contributing to the reaction (reaction solution amount remaining between reaction by-products) (kg / min)

The hydrogen gas generation amount Gh2 (kg / min) is proportional to Gw corresponding to the dissolution rate of the hydrogen generating agent. The variation ΔPr of the pressure Pr in the hydrogen generation container is proportional to the difference between the hydrogen gas generation amount Gh2 in the hydrogen generation apparatus 10 and the hydrogen consumption amount Gfc (kg / min) in the fuel cell 2. That is, it is expressed by equations (5) and (6).
ΔPr∝ (Gh2−Gfc) (5)
Pr∝∫ (Gh2-Gfc) dt (6)

  Actually, Gw may change depending on the reaction temperature and the production status of reaction byproducts. Gfc is constant at constant output. Gh2 is greatly affected by the reaction temperature. Gh2 is transiently independent on the upstream side and the downstream side of the pressure regulating valve 8. Because of the above conditions, the control unit 20 controls Gw so that the pressure Pr measured by the pressure gauge 22 approaches a predetermined value (so as to be within a predetermined numerical range).

  The control unit 20 controls the amount of water supplied to the reaction vessel 30 by a pump 13 installed in the reaction solution supply pipe 12. When the pump 13 is a constant capacity type, the control unit 20 controls the number of rotations of the pump to control the water supply amount. When the pump 13 is a centrifugal pump, a flow meter is installed in the reaction solution supply pipe 12, and the control unit 20 controls the water supply amount while monitoring the flow rate of water flowing through the reaction solution supply pipe 14.

(B) Temperature control When the water supply amount is constant, the reaction rate increases as the water temperature increases, and the hydrogen gas generation amount Gh2 increases. Formula (3) is an exothermic reaction, and the temperature of the reaction solution rises as the reaction proceeds. In this embodiment, in order to manage to the reaction solution temperature (50 degreeC-150 degreeC) mentioned above, the hydrogen gas temperature from the inside of the reaction container 30, the water supply amount from the tank 11, and water temperature are controlled.

  Specifically, the control unit 20 operates the pump 19 of the second cooler 16. The second cooler 16 cools the temperature of water supplied from the tank 11 to 50 ° C. or less by heat exchange.

The control unit 20 stores temperatures T ₁ , T ₂ , and T ₃ (T ₁ <T ₂ <T ₃ ). The temperatures T ₁ and T ₂ are temperatures in the range of 50 ° C. to 150 ° C., which is the hydrogen gas temperature of the present embodiment. The temperatures T ₁ and T ₂ are set as appropriate according to the output of the fuel cell. For example, T ₁ = 80 ° C. and T ₂ = 120 ° C. Temperature _{T 3} is the upper limit value 0.99 ° C. reaction temperature. In the following, two temperatures (T ₁ , T ₂ ) are set as threshold values within the reaction temperature range, but one point or a plurality of points may be used. However, from the viewpoint of temperature management and controllability, it is preferable to set the threshold value to two points.

If the hydrogen gas temperature T measured by the thermometer 21 is T <T _1, the first cooler 15 is not activated. Further, the control unit 20 maintains the rotational speed of the pump 13 so that the water in the tank 11 is supplied to the reaction vessel 30 at a predetermined flow rate Gws.

When the hydrogen gas temperature T is T ₁ ≦ T ≦ T ₂ , the control unit 20 operates the first cooler 15. The control unit 20 varies the rotational speed of the pump 18 of the first cooler 15 according to the hydrogen gas temperature T, thereby varying the amount of circulating water supplied to the first cooler 15. Specifically, the control unit 20 stores the temperature T ₁ , T ₂ and the set value Rs of the rotation speed of the pump 18 at the temperature T ₂ , and is measured based on T ₁ , T ₂ , Rs. As the hydrogen gas temperature T increases, the rotational speed of the pump 18 is increased linearly. At this time, the control unit 20 maintains the water supply amount Gws from the reaction solution supply unit 33.

When the hydrogen gas temperature T is T ₂ <T ≦ T ₃ , the control unit 20 maintains the rotation speed of the pump 18 of the first cooler 15 at the rotation speed setting value Rs at T ₂ . In addition, the control unit 20 varies the number of rotations of the pump 13 according to the hydrogen gas temperature T, and decreases the amount of water supplied from the reaction solution supply unit 33. Specifically, the control unit 20, and stores the temperature _T 2, _{T 3,} the water supply amount Gws ₂ at temperature _{T 2,} the water supply amount Gws ₃ at a temperature _{T 3.} However, Gws ₂ = Gws and Gws ₃ = 0. Based on T ₂ , T ₃ , Gws ₂ , and Gws ₃ , the controller 20 linearly decreases the rotational speed of the pump 13 as the measured hydrogen gas temperature T increases.

When T> T ₃ , the control unit 20 maintains the rotational speed of the pump 18 of the first cooler 15 at the set value Rs until the hydrogen gas temperature becomes equal to or lower than T ₃ , and from the reaction solution supply unit 33. Stop water supply.

<Stopping process (FIG. 5B)>
When stopping the hydrogen generation with the hydrogen generating agent 34 remaining, the control unit 20 stops the pump 13 to stop the water supply from the tank 11. After the pump 13 is stopped, the portion of the hydrogen generating agent 34 that has been immersed in the reaction solution reacts with the reaction solution. However, when the hydrogen generating agent 34 and the reaction solution do not come into contact with each other, the generation of hydrogen stops.

<Resuming step (FIGS. 5C and 5D)>
When restarting the generation of hydrogen, the controller 20 operates the pump 13 to supply water into the reaction vessel 30. At this time, the water supplied from the reaction solution supply unit 33 does not stir the reaction by-products and the reaction solution stored in the bottom of the reaction vessel 30 so that only the alkali metal hydroxide aqueous solution is easily generated on the surface layer. Water is supplied or sprayed along the wall surface of the reaction vessel 30 and the hydrogen generating agent 34. Since the reaction by-product and the alkali metal hydroxide aqueous solution have a higher specific gravity than water, the supplied water forms a layer of the reaction solution 35 on the mixed layer 36 as shown in FIG. Due to diffusion due to the concentration difference with the mixed layer 36 and when the water flows along the wall surface, the mixed layer 36 and water are mixed in the vicinity of the wall surface. Will be included. The hydrogen generating agent 34 and the reaction solution 35 come into contact with each other to return to the active state. Thereby, as shown in FIG. 5 (d), the expressions (1) to (3) are started, the generation of hydrogen is resumed, and the reaction state before the stop is restored.

Second Embodiment
FIG. 7 is a schematic diagram of the hydrogen generator of the second embodiment. In FIG. 7, the same components as those in FIGS.

  As shown in FIG. 7A, in the hydrogen generator 50 of the second embodiment, a support unit movable device 51 is installed on the outer upper part of the reaction vessel 30. The support part movable device 51 is connected to the support part 31. The support part movable device 51 enables the support part 31 to move up and down. As the support portion 31 moves, the hydrogen generating agent 34 also moves up and down. The support unit movable device 51 is connected to the control unit 20.

  The operation method of the hydrogen generator according to the second embodiment will be described with reference to FIG. In the second embodiment, the storage process, the reaction process, and the discharge process are the same as those in the first embodiment. This embodiment is different from the first embodiment in the stop process and the restart process.

<Stop process (FIG. 7B)>
When stopping the hydrogen generation with the hydrogen generating agent 34 remaining, the control unit 20 stops the pump 13 to stop the water supply from the tank 11. Simultaneously with the stop of the pump 13, the control unit 20 operates the support unit moving device 51 to displace the support unit 31 above the reaction vessel 30. Thereby, the hydrogen generating agent 34 is also displaced above the reaction vessel 30. When the lower end of the hydrogen generating agent 34 is positioned above the liquid level of the reaction solution 35, the generation of hydrogen stops.

<Resumption process>
When restarting the generation of hydrogen, the control unit 20 operates the pump 13 to supply water from the reaction solution supply unit 33 into the reaction vessel 30. The control unit 20 operates the support unit movable device 51 to displace the support unit 31 below the reaction vessel 30. Then, as shown in FIG. 7A, the hydrogen generating agent 34 and the reaction solution 35 come into contact with each other, the expressions (1) to (3) are started, and the generation of hydrogen resumes.

  When the support unit movable device 51 is installed as in the present embodiment, the time delay until the hydrogen generation is stopped or restarted from the command of the control unit 20 in the stop process and the restart process can be significantly shortened. The hydrogen generation can be stopped and restarted quickly.

<Third Embodiment>
FIG. 8 is a schematic view of the hydrogen generator of the third embodiment. In FIG. 8, the same components as those in FIGS.

  In the hydrogen generator 60 of the third embodiment, the reaction vessel 30 is divided into a plurality of reaction chambers 62a to 62c (first reaction chambers) by a partition wall (first partition wall) 61 as shown in FIG. ing. The partition wall 61 is connected to the bottom wall of the reaction vessel 30 and is not connected to the upper wall. A plurality of reaction chambers can also be installed in the depth direction of the page. In FIG. 8A, the upper end portion of the partition wall 61 is positioned below the upper end of the hydrogen generating agent 34, but may be positioned above the upper end portion of the partition wall 61 and the upper end of the hydrogen generating agent. The positions may match.

  In FIG. 8A, one hydrogen generating agent 34 is stored in each of the reaction chambers 62a to 62c, but a plurality of hydrogen generating agents 34 are stored in one reaction chamber 62a to 62c. May be.

  A reaction solution supply unit 33 is provided at a position corresponding to one reaction chamber 62 a (one chamber of the first reaction chamber) above the reaction vessel 30. No reaction solution supply unit is installed at a position corresponding to the other reaction chambers 62b and 62c (other chambers of the first reaction chamber).

A hydrogen generation method using the hydrogen generator 60 of the third embodiment will be described with reference to FIG.
<Storing process (FIG. 8A)>
The hydrogen generating agent 34 is accommodated by being suspended in the vertical direction by the support portion 31 installed on the upper wall of each first reaction chamber divided by the partition wall 61 in the reaction vessel 30. In the fuel cell system 1 in which the starter 14 is not provided, as shown in FIG. 8A, an alkali metal hydroxide 63 is accommodated in the bottom of the reaction chamber 62a in which the reaction solution supply unit 33 is provided. The alkali metal hydroxide may be a solid or an aqueous solution.

<Reaction solution supply step (FIG. 8B)>
The pump 13 is activated and the water in the tank 11 is conveyed from the tank 11 toward the reaction vessel 30. Water flows into the reaction chamber 62a from the reaction solution supply unit 33, and the alkali metal hydroxide and water are mixed in the reaction chamber 62a to generate a reaction solution.
When installing the starter 14 as shown in FIG. 4, the reaction solution produced by mixing with the alkali metal hydroxide in the starter 14 flows from the reaction solution supply unit 33 into the reaction chamber 62a.

<Reaction process (FIG. 8C)>
When the reaction solution and the hydrogen generating agent 34 in the reaction chamber 62a come into contact with each other, hydrogen is generated according to the equations (1) to (3) as in the first embodiment. When the supply of water from the reaction solution supply unit 33 is continued, the reaction solution overflows from the reaction chamber 62a and flows into the reaction chamber (reaction chamber 62b in FIG. 8) adjacent to the reaction chamber 62a. In the reaction chamber 62a, the liquid level of the reaction solution reaches the upper end of the partition wall 61, and the rise of the liquid level of the reaction solution in the reaction chamber 62a stops. When the end of the hydrogen generating agent 34 in the reaction chamber 62a does not come into contact with the reaction solution, the hydrogen generation in the reaction chamber 62a ends.

In the reaction chamber 62b, the reaction solution is supplied from the reaction chamber 62a, and the water level of the reaction solution rises. When the hydrogen generating agent 34 and the reaction solution come into contact with each other, hydrogen is generated according to the formulas (1) to (3) as in the first embodiment. When the water level of the reaction solution in the reaction chamber 62b reaches the upper end of the partition wall 61, the reaction solution flows into the reaction chamber 62c and the generation of hydrogen in the reaction chamber 62b ends.
This reaction process is repeated until all the hydrogen generating agents 34 in the reaction vessel 30 have been reacted.

  When the concentration taken in between the reaction by-products during the reaction step decreases, an aqueous solution of alkali metal hydroxide is replenished from the reaction solution supply unit 33 as in the first embodiment.

<Discharge process (FIGS. 8B and 8C)>
The generated hydrogen passes through the space between the upper end of the partition wall 61 and the upper wall of the reaction vessel 30, and is discharged from the hydrogen generator 60 through the hydrogen discharge unit 32.

<Stopping process, resuming process>
In the hydrogen generator 60 of the third embodiment, when hydrogen generation is stopped in a state where the hydrogen generating agent 34 remains, the stop process and the regeneration process are performed by the same steps as in the first embodiment.

  As another example of the third embodiment, the hydrogen generator 60 may include the support unit movable device described in the second embodiment. In this case, as described in the second embodiment, the hydrogen generating agent is displaced up and down using the support unit moving device in the stopping process and the regeneration process.

<Fourth embodiment>
FIG. 9 is a schematic view of the hydrogen generator of the fourth embodiment. In FIG. 9, the same components as those in FIGS.

  In the hydrogen generator 70 of the fourth embodiment, the reaction vessel 30 is divided into a plurality of reaction chambers 72a to 72c (second reaction chambers) by a partition wall (second partition wall) 61 as shown in FIG. ing. The partition wall 61 is connected to the bottom wall of the reaction vessel 30 and also to the upper wall. On the upper wall side of the partition wall 61, partitions 73a and 73b each having aluminum as a main component are installed. A plurality of reaction chambers 72a to 72c can be installed in the depth direction of the drawing. In FIG. 9A, the lower ends of the partitions 73a and 73b are positioned below the upper end of the hydrogen generating agent 34, but may be positioned above or the lower ends of the partitions 73a and 73b and the hydrogen generation. The position of the upper end of the agent may be the same.

  In FIG. 9A, one hydrogen generating agent 34 is stored in one reaction chamber, but a plurality of hydrogen generating agents 34 may be stored in one reaction chamber.

  A reaction solution supply unit 33 is provided above one reaction chamber 72a (one chamber of the second reaction chamber). The reaction solution supply section is not installed in the other reaction chambers 72b and 72c (one other chamber in the second reaction chamber).

  Water 78 is filled in the reaction chambers 72b and 72c in which the reaction solution supply unit 33 is not installed. The bottoms of the reaction chambers 72b and 72c are connected by a circulation line 74. The circulation line 74 has a pump 75. Valves 76a and 76b are installed in the lines from the reaction chambers 72b and 72c, respectively. In the middle of the circulation line 74, the reaction solution supply pipe 12 is connected.

  Hydrogen discharge portions 77a to 77c are installed in the reaction chambers 72a to 72c, respectively. The hydrogen discharge units 77 a to 77 c are connected to the hydrogen supply unit 7.

A hydrogen generation method using the hydrogen generator 70 of the fourth embodiment will be described with reference to FIG.
<Storing process (FIG. 9A)>
Similarly to the first embodiment, the hydrogen generating agent 34 is vertically moved by the support portion 31 installed on the upper wall of each of the second reaction chambers 72 a to 72 b divided by the partition wall 61 in the reaction vessel 30. Suspended in the direction and stored. Further, in the fuel cell system 1 not provided with the starter 14, as shown in FIG. 8A, an alkali metal hydroxide 63 is accommodated in the bottom of the reaction chamber 72a in which the reaction solution supply unit 33 is provided. . The alkali metal hydroxide may be a solid or an aqueous solution.
Even if the hydrogen generator 34 mainly composed of aluminum and the partitions 73a and 73b are in contact with the water 78 in the reaction chambers 72b and 72c, there is no alkali component, so that the formulas (1) to (3) The reaction does not proceed.

<Reaction Solution Supply Step (FIGS. 9A and 9B)>
When the pump 75 is activated and the valve 76a is opened, the water 78 in the reaction chamber 72b is conveyed toward the reaction chamber 72a by the circulation line 74. Water flows into the reaction chamber 72a from the reaction solution supply unit 33, and the alkali metal hydroxide and water are mixed in the reaction chamber 72a to generate a reaction solution.

  When the activation device 14 is installed as shown in FIG. 4, the pump 13 is activated, and the water in the tank 11 flows into the activation device 14. The reaction solution generated by mixing with the alkali metal hydroxide in the starter 14 flows from the reaction solution supply unit 33 into the reaction chamber 72a.

<Reaction process (FIG. 9 (c))>
When the reaction solution and the hydrogen generating agent 34 in the reaction chamber 72a come into contact with each other, hydrogen is generated according to the equations (1) to (3) as in the first embodiment. When the liquid level of the reaction solution in the reaction chamber 72a reaches the partition 73a, the reactions of formulas (1) to (3) occur between the partition 73a and the reaction solution. By this reaction, the partition 73a is dissolved and penetrates between the reaction chambers 72a and 72b.

  Since the supply of water from the reaction solution supply unit 33 is continued, the reaction solution flows from the reaction chamber 72a through the penetrating portion of the partition 73a and into the reaction chamber 72b adjacent to the reaction chamber 72a. In the reaction chamber 72a, the rise of the liquid level of the reaction solution stops. When the end of the hydrogen generating agent 34 in the reaction chamber 72a is no longer in contact with the reaction solution, the hydrogen generation in the reaction chamber 72a is completed.

  In the reaction chamber 72b, the reaction solution is supplied from the reaction chamber 72a, and the water level of the reaction solution rises. When the hydrogen generating agent 34 and the reaction solution come into contact with each other, hydrogen is generated according to the formulas (1) to (3) as in the first embodiment. When the water level of the reaction solution in the reaction chamber 72b reaches the partition 73b, the partition 73b dissolves and the reaction solution flows into the reaction chamber 72c, and the generation of hydrogen in the reaction chamber 72b ends.

  When the water in the reaction chamber 72b runs out, the valve 76a is closed. Next, the valve 76 b is opened, and the water 78 in the reaction chamber 72 c is conveyed to the reaction solution supply unit 33 through the circulation line 74.

When the concentration taken in between the reaction by-products during the reaction step is reduced, the alkali metal hydroxide aqueous solution is supplied from the reaction solution supply pipe 12 and the reaction solution supply unit 33 as in the first embodiment. To be replenished.
This reaction process is repeated until all the hydrogen generating agents 34 in the reaction vessel 30 have been reacted.

  Here, when the reaction solution flows into the reaction chambers 72b and 72c, the water level stored in the reaction chambers 72b and 72c in advance is lower than the lower end of the hydrogen generating agent 34, or the reaction chamber 72b. , 72c is preferably not present. In this way, the amount of water stored in the reaction chambers 72b and 72c is determined.

  Since all of the hydrogen generating agent 34 cannot be reacted only with the amount of water in the reaction chambers 72 b and 72 c, the shortage is supplied from the tank 11 to the hydrogen generator 70 through the reaction solution supply pipe 12 and the reaction solution supply unit 33. .

<Discharge process (FIGS. 9B and 9C)>
Hydrogen generated in each reaction chamber 72a is discharged from the hydrogen generator 70 through the hydrogen discharge portion 77a. When hydrogen is generated in the reaction chambers 72b and 72c, hydrogen is discharged mainly from the hydrogen discharge portions 77b and 77c of the reaction chambers 72b and 72c in which the reaction is taking place, but part of the hydrogen passes through the through portions of the partitions 73a and 73b. Also discharged from the hydrogen discharge portions 77a and 77b of the reaction chamber.

<Stopping process, resuming process>
When hydrogen generation is stopped in a state where the hydrogen generating agent 34 remains in the hydrogen generator 70 of the fourth embodiment, the stop process and the regeneration process are performed by the same steps as in the first embodiment.

  As another example of the fourth embodiment, the hydrogen generator 70 may include the support unit moving device described in the second embodiment. In this case, as described in the second embodiment, the hydrogen generating agent is displaced up and down using the support unit moving device in the stopping process and the regeneration process.

  In each of the above embodiments, hydrogen discharged from the hydrogen generator may contain an alkali metal hydroxide such as NaOH. When the alkali metal hydroxide flows into the fuel cell 2, the polymer membrane of the fuel cell 2 is adversely affected. In the fuel cell system 1, a temperature control humidity tank for removing alkali metal hydroxide is installed between the pressure control valve 8 and the hydrogen generator and upstream of the hydrogen gas of the thermometer 21 and the pressure gauge 22. May be.

  FIG. 10 is an example of a temperature-controlled humidity tank. The temperature control / humidity tank 90 is connected to the tank 12 by a supply line 91 and a return line 92. A water level meter 93 is installed in the temperature control / humidity tank 90, and water is supplied from the tank 11 to the temperature control / humidity control tank 90 so as to reach a predetermined water level.

  A cooler 94 is installed so as to be immersed in the water in the temperature-controlled humidity tank 90. A coolant such as seawater is supplied to the cooler 94 by a pump 95.

  The hydrogen generator is connected to the bottom of the temperature-controlled humidity tank 90 through a hydrogen supply pipe 96 a of the hydrogen supply unit 7. The upper part of the temperature control / humidity tank 90 is connected to the fuel cell 2 by a hydrogen supply pipe 96 b of the hydrogen supply unit 7.

  The hydrogen gas discharged from the hydrogen generator 11 is supplied into the water in the temperature-controlled humidity tank 90 through the hydrogen supply pipe 96a. The alkali metal hydroxide in the hydrogen gas is dissolved in the water, and only the hydrogen gas is supplied to the fuel cell 2 from the hydrogen supply pipe 96b. Since the hydrogen gas from the hydrogen generator is high temperature, the water in the temperature control and humidity tank 90 evaporates, the water level decreases, and the temperature of the water increases. Water is replenished from the tank 11 when the water level measured by the water level gauge becomes a predetermined value or less. Moreover, when the temperature of water becomes more than a predetermined value, the cooler 94 is operated, and heat exchange is performed between the refrigerant and the water to cool the water.

A test for confirming the progress of the reaction described in the above embodiment was performed.
An aqueous NaOH solution (7 mol / l, about 100 ml) was placed in the graduated cylinder. A plate-shaped pure aluminum piece was suspended with a string, and a predetermined amount was immersed in an aqueous NaOH solution. At this time, the aluminum pieces were weighed in advance, and the aluminum was dissolved while controlling the amount of aluminum pieces immersed in the NaOH aqueous solution while checking the amount of dissolved Al. At this time, since the supplied water was consumed by the reaction, it was supplied while measuring twice the equivalent amount of water including the evaporated content.

As a result of the above test, it was confirmed that double equivalent of aluminum (19 g × 2 times) was dissolved in water and hydrogen was generated in a test in which water was added. From this test result, it can be said that the reaction of the formula (3) occurs in the presence of NaOH.
As the reaction continued, black and white precipitates were observed. This precipitate was estimated to be Al (OH) ₃ and the liquid phase became shallow due to the deposition of the precipitate. It has been confirmed that the increase in deposits at this time is about 8 to 10 times the amount of aluminum dissolved. This situation was continued until the end of the test due to the capacity limitation of the graduated cylinder. In this test, a thermocouple was immersed in the liquid in the container, and the temperature during the reaction was measured. When the liquid temperature was 50 ° C. or higher, the reaction rate was faster and the amount of hydrogen generated was larger than when the liquid temperature was room temperature. In addition, droplets were scattered on the wall of the container and deposits were observed. This confirmed the necessity of liquid phase temperature control and the like.

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Fuel cell 3 Lithium secondary battery 4 Load 5 Oxygen generator 6 Oxygen supply part 7 Hydrogen supply part 8 Pressure regulating valve 9 Heat exchanger 10, 50, 60, 70 Hydrogen generator 11 Tank 12 Reaction solution supply piping 13, 18, 19, 75, 95 Pump 14 Starter 15, 16, 17, 94 Cooler 20 Control unit 21 Thermometer 22 Pressure gauge 30 Reaction vessel 31 Support unit 32, 77 Hydrogen discharge unit 33 Reaction solution supply unit 34, 40 Hydrogen generating agent 35 Reaction solution 36 Mixed layer 37 Deposited layer 51 Supporting portion movable device 61 Partition walls 62a to 62c, 72a to 72c Reaction chamber 63 Alkali metal hydroxide 73 Partition 74 Circulation lines 76a and 76b Valve 78 Water 90 Temperature control Humidity tank 91 Supply line 92 Return line 93 Water level gauges 96a, 96b Hydrogen supply piping

Claims (16)

A reaction vessel containing a hydrogen generator mainly composed of aluminum, capable of reacting with the hydrogen generator at the bottom, and capable of containing a reaction solution containing an alkali metal hydroxide;
A support part capable of hanging and supporting the hydrogen generating agent from the upper part of the reaction vessel;
A hydrogen discharge part for discharging the hydrogen gas generated by the reaction between the hydrogen generating agent and the reaction solution from the reaction vessel;
A reaction solution supply unit for supplying water consumed in the reaction into the reaction container from the upper part of the reaction container;
A control unit for controlling the concentration of the alkali metal hydroxide in the reaction solution within a predetermined concentration and controlling the temperature of the reaction solution to a predetermined value;
A predetermined region at the lower end of the hydrogen generating agent is brought into contact with the reaction solution, the hydrogen generating agent and the reaction solution are reacted to generate a predetermined amount of the hydrogen gas, and the reaction does not include the alkali metal. A hydrogen generator for depositing by-products on the bottom of the reaction vessel.   Based on the pressure and temperature of the hydrogen gas discharged from the hydrogen discharge unit, the control unit sets the concentration of the alkali metal hydroxide in the reaction solution stored in the reaction vessel to 1 mol / L. The hydrogen generator according to claim 1, wherein the hydrogen generator is controlled to 14 mol / L or less and the temperature of the reaction solution is controlled to 50 ° C. or more and 150 ° C. or less.   2. The hydrogen generator according to claim 1, wherein a ratio of a cross-sectional area of the hydrogen generating agent to a cross-sectional area of the reaction vessel is 5 to 15 times. A first partition wall whose upper end is connected to the bottom wall of the reaction vessel and is spaced apart from the upper wall divides the internal space of the reaction vessel into a plurality of first reaction chambers, and each of the first reaction chambers Contains the hydrogen generating agent,
The reaction solution supply unit is provided in an upper part of the chamber of the first reaction chamber, the reaction solution supply unit supplies the water to the chamber of the first reaction chamber;
The reaction solution in one chamber of the first reaction chamber can flow into another chamber of the adjacent first reaction chamber through a space between the first partition and the upper wall of the reaction vessel. The hydrogen generator according to any one of claims 1 to 3. A second partition connected to a bottom wall and an upper wall of the reaction vessel divides the internal space of the reaction vessel into a plurality of second reaction chambers, and each of the second reaction chambers contains the hydrogen generating agent. And
A partition mainly composed of aluminum is installed on top of the second partition;
The reaction solution supply unit is provided in an upper part of the chamber of the second reaction chamber, the reaction solution supply unit supplies the water to the chamber of the second reaction chamber;
The reaction solution dissolves the partition, and the reaction solution in one chamber of the second reaction chamber can flow into another chamber of the adjacent second reaction chamber through the space in which the partition is installed. The hydrogen generator according to any one of claims 1 to 3.   The other chamber in the second reaction chamber contains the water, the other second reaction chamber and the reaction solution supply unit are connected via a pipe, and a pump installed in the pipe is connected to the other The hydrogen generator according to claim 5, wherein the water in the second reaction chamber is transported to a chamber of the second reaction chamber.   7. The control unit according to claim 1, wherein the control unit stops supply of the water to stop generation of the hydrogen gas, and restarts supply of the water to restart generation of the hydrogen gas. The hydrogen generator described. The apparatus further includes a support unit moving device capable of moving the support unit up and down at the top of the reaction vessel,
The control unit drives the support unit movable device to raise the hydrogen generating agent to stop the generation of the hydrogen gas, and lower the hydrogen generating agent to restart the generation of the hydrogen gas. The hydrogen generator according to any one of claims 1 to 6.   A fuel cell system comprising the hydrogen generator according to any one of claims 1 to 8. A storage step of suspending a hydrogen generating agent mainly composed of aluminum from the upper part of the reaction vessel and storing it in the reaction vessel);
A reaction solution supplying step of supplying water into the reaction container until a reaction solution containing an alkali metal hydroxide reaches a predetermined liquid level in the reaction container;
The lower end of the hydrogen generator and the reaction solution are in contact with each other, the concentration of the alkali metal hydroxide in the reaction solution is controlled within a predetermined concentration, and the temperature of the reaction solution is controlled to a predetermined value. A reaction step in which a predetermined amount of hydrogen gas is generated by the reaction between the hydrogen generating agent and the reaction solution, and a reaction by-product not containing the alkali metal is deposited at the bottom of the reaction solution;
A hydrogen generation method including a discharge step of discharging the hydrogen gas from the reaction vessel.   In the reaction step, the concentration of the alkali metal hydroxide in the reaction solution stored in the reaction vessel is controlled to 1 mol / L or more and 14 mol / L or less, and the temperature of the reaction solution is 50. The method for generating hydrogen according to claim 10, wherein the method is controlled to be at least 150 ° C.   The hydrogen generating method according to claim 10, wherein the hydrogen generating agent having a ratio of a cross-sectional area of the hydrogen generating agent to a cross-sectional area of the reaction vessel of 5 to 15 times is accommodated in the reaction vessel. In the storing step, the hydrogen generating agent is placed in each of the first reaction chambers in which the inner space of the reaction vessel is divided into a plurality of portions by a first partition wall whose upper end is spaced apart from the upper wall of the reaction vessel. Stowed,
In the reaction solution supply step, the water is supplied to one chamber of the first reaction chamber,
In the reaction step, the hydrogen gas is generated by contacting the reaction solution containing the alkali metal hydroxide with the hydrogen generating agent in the first reaction chamber in one chamber of the first reaction chamber. And
After one chamber of the first reaction chamber is filled with the reaction solution, the reaction is performed in another chamber of the first reaction chamber adjacent to the one chamber of the first reaction chamber containing the reaction solution. The method for generating hydrogen according to any one of claims 10 to 12, wherein the solution flows in. In the storing step, a plurality of internal spaces of the reaction vessel are provided by a second partition wall that is connected to a bottom wall and an upper wall of the reaction vessel and a partition mainly composed of aluminum is installed on the upper wall side. The hydrogen generating agent is stored in each of the second reaction chamber partitioned by
In the reaction solution supply step, the water is supplied to one chamber of the second reaction chamber,
In the reaction step, the hydrogen gas is generated by contacting the reaction solution containing the alkali metal hydroxide in the chamber of the second reaction chamber with the hydrogen generating agent in the chamber of the second reaction chamber. And
The partition and the reaction solution in the second reaction chamber come into contact and react, and the partition dissolves in the reaction solution,
The said reaction solution flows into the other chamber of the said 2nd reaction chamber adjacent to the one chamber of the said 2nd reaction chamber which accommodates the said reaction solution through the space in which the said partition was installed. 12. The method for generating hydrogen according to any one of 12 above. In the storing step, the water is stored in another chamber of the second reaction chamber other than the one of the second reaction chamber,
The hydrogen generation method according to claim 14, wherein in the reaction step, the water stored in the storage step is transported to one chamber of the second reaction chamber. The reaction step is a step of stopping the generation of the hydrogen gas by stopping the supply of the water or raising the hydrogen generating agent;
The hydrogen generation method according to claim 10, further comprising a restarting step of restarting the generation of the hydrogen gas by restarting the supply of water or lowering the hydrogen generating agent. .

Images